1. Field of the Invention
This invention relates to a system for controlling a data transfer between computers connected each other through a public telephone line by dialing up. Particularly, this invention relates to a system for controlling the data transfer, which can manage a failure occurred during a transmission processing.
2. Description of the Related Art
Basically, there are two methods for connecting the computer to the Internet, i.e., a method for connecting the computer through the public telephone line by dialing up and a method for connecting the computer through a leased line.
In the method for connecting the computer by dialing up, the computer is not always connected to a network, e.g., the Internet, etc. When it is necessary, the computer is connected to the network through the public telephone line. Therefore, when a transmission data amount and a number of transmissions are small, this method is cheaper than the method using the leased line. Recently, this method is more adopted in a remote monitoring and controlling system of a small factory, etc.
A method related to this invention is disclosed in xe2x80x9cA Direct Function Program between Internet users according to an IP Address Switching and its System,xe2x80x9d in Japanese Unexamined Published Patent Application Hei 10-149325.
FIG. 18 illustrates a configuration of a transmission system between computers connected each other by dialing up according to the related art.
In FIG. 18, a server function program 1801 is provided in the Internet. The server function program 1801 manages IP (Internet protocol) addresses and current conditions of end-users centrally, who have logged in the Internet. In a side of the end-users of the Internet, client function programs 1802a and 1802b are provided. The client function program of the end-user sends its own IP address and current condition to the server function program 1801, and receives an IP address of another end-user, with which the end-user wants to communicate, from the server function program 1801.
According to this method, the client function programs 1802a and 1802b of the end-users, who have logged in the Internet, send their own IP addresses and current conditions to the server function program 1801 respectively. The client function programs 1802a and 1802b receive current IP addresses of other end-users from the server function program 1801 to connect to the other end-users directly, and send the current IP addresses to dialogue transmission systems 1804a and 1804b. Accordingly, the end-users can be connected each other directly, and a transmission processing can be realized.
A method related to this invention is also disclosed in xe2x80x9cA Calling Method of a Transmission Apparatus Connected by Dialing Up and its Monitoring and Controlling System,xe2x80x9d in Japanese Unexamined Published Patent Application Hei 10-155040.
FIG. 19 illustrates a configuration of a transmission system between computers connected each other by dialing up according to the related art.
In FIG. 19, each of transmission apparatuses 1902 and 1903 including connectors, computers, and telephones are connected to a telephone line 1904. The transmission apparatuses 1902 and 1903 are connected to Internet providers 1905 and 1906 via the telephone line 1904 respectively, and the Internet providers 1905 and 1906 are connected each other via Internet 1907.
According to this method, the transmission apparatus 1902 calls the transmission apparatus 1903 via the telephone line 1904, and sends a request for connecting to the transmission apparatus 1903. Then, both of the transmission apparatuses 1902 and 1903 disconnect the telephone line 1904 once. Then, the transmission apparatuses 1902 and 1903 call neighboring Internet providers 1905 and 1906, and connect to the Internet 1907 respectively. The transmission apparatuses 1902 and 1903 send their own IP addresses to e-mail addresses each other by e-mails. When both of the transmission apparatuses 1902 and 1903 confirm the IP addresses each other, both of the transmission apparatuses 1902 and 1903 can process the transmission by using the IP addresses in the Internet 1907.
According to the related art, the processing is performed as stated in the transmission system between the computers connected each other by dialing up. However, since a recovery processing from a failure is not considered, when a failure is occurred in the network during a transmission processing, the processing between the computers must be suspended, and restarted from a beginning of the processing.
Further, when a transmission apparatus and an Internet provider are disconnected due to a failure between the computers connected by dialing up, a user has to perform a troublesome operation for reconnecting.
Further, when the transmission is processed by using the Internet, possibilities of a loss of a packet and a transmission failure tend to increase in proportion to an increase of a data size of transmission data. Since a size of data transmitted between the computers is not considered according to the related art, when a transmission of data in a long size is processed, a reliability of the transmission can not be guaranteed.
Accordingly, it is an object of this invention to solve the above-stated problems in the related art. Even if a failure is occurred in the network, the processing can be continued by using a provided data retransmission function.
It is another object of this invention to reconnect to the Internet automatically in case that the connection to the Internet provider is disconnected by providing a provider information manager for managing connection information to the Internet provider.
It is also another object of this invention to ensure a reliability in a transmission processing of a long packet in the Internet by providing a packet-division transferor.
According to one aspect of this invention, a computer system for controlling a data transfer includes a first computer system for connecting to the Internet by dialing up an Internet provider, and a second computer system connected to the Internet.
The first computer system includes a provider connector, a first connection information memory, and a first data transferor. The provider connector receives an address of the first computer system from the Internet provider at a time of dialing up the Internet provider, the first connection information memory stores the received address of the first computer system, and the first data transferor sends the received address of the first computer system to the second computer system. Then, the provider connector receives a new address of the first computer system from the Internet provider at a time of redialing up the Internet provider, and the first data transferor sends the original address of the first computer system stored in the first connection information memory and the received new address of the first computer system to the second computer system.
The second computer system includes a second connection information memory and a second data transferor. The second data transferor receives the original address of the first computer system from the first computer system, and the second connection information memory stores the received original address of the first computer system. Then, the second data transferor receives the original address of the first computer system and the new address of the first computer system, and transfers data using the received new address of the first computer system as an address of the first computer system in case that the address of the first computer system stored in the second connection information memory and the received original address of the first computer system are matched.
According to another aspect of this invention, the computer system for controlling the data transfer connected to the Internet provider includes a provider information memory for storing a provider management information necessary for connecting to the Internet provider, and a provider connection performer for selecting an Internet provider for reconnecting to the Internet based on the provider management information stored in the provider information memory, and requesting the selected Internet provider to connect in case of being disconnected from the Internet provider.
According to another aspect of this invention, the computer system for controlling the data transfer connected to the Internet provider for sending requested data to the Internet includes a data transferor, a requested data memory, and a provider connection performer. The data transferor doesn""t send the requested data in case of being disconnected from the Internet provider, and the requested data memory stores the requested data, which have not been sent. The provider connection performer requests connecting to one of the Internet provider and another Internet provider in case of being disconnected from the Internet provider, and the data transferor reads out the requested data stored in the requested data memory after being connected to the Internet provider, and sends the read-out requested data to the connected Internet provider.
According to another aspect of this invention, the computer system for controlling the data transfer includes a sending computer system for sending requested data using the Internet in accordance with a protocol of a connectionless type, and a receiving computer system for receiving the requested data using the Internet in accordance with the protocol of the connectionless type. The sending computer system includes a sending data transferor, and the receiving computer system comprises a receiving data transferor. The sending data transferor sends the requested data to the receiving computer system using the Internet in accordance with the protocol of the connectionless type, and the receiving data transferor receives the requested data from the sending computer system using the Internet in accordance with the protocol of the connectionless type, and sends an arrival confirmation message to the sending computer system after receiving the requested data. Then, the sending data transferor judges if the arrival confirmation message is received from the receiving computer system after an arrival confirmation time is passed after sending the requested data, and retransmits the requested data using the Internet in accordance with the protocol of the connectionless type in case that the arrival confirmation message is not received.
Further features and applications of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Other objects features, and advantages of the invention will be apparent from the following description when taken in conjunction with the accompany drawings.